NEW YORK -- The nation's financial system needs tougher regulations and stronger supervision to protect against future crises, Federal Reserve Bank of New York President Timothy Geithner said Monday in a speech calling for greater central bank authority over markets and financial institutions.

Mr. Geithner said the New York Fed on Monday is hosting 17 firms that represent 90% of trading in credit derivatives, and they will discuss oversight and market infrastructure and reduce vulnerabilities in lending markets. Among the changes...